<template>
<!-- 轮播图 -->
  <div class="xtx-carousel" @mouseenter="stop()" @mouseleave="start()">
    <ul class="carousel-body">
      <li class="carousel-item " v-for="(item,i) in sliders" :key="i" :class="{fade:index===i}">
        <!-- 普通轮播图 -->
        <RouterLink v-if="item.hrefUrl" :to="item.hrefUrl">
          <img
            v-lazy="item.imgUrl"
            alt=""
          />
        </RouterLink>
        <!-- 同类推荐轮播图 -->
        <div v-else class="slider">
          <RouterLink v-for="goods in item" :key="goods.id" :to="`/product/${goods.id}`">
            <img :src="goods.picture" alt="">
            <p class="name ellipsis">{{goods.name}}</p>
            <p class="price">&yen;{{goods.price}}</p>
          </RouterLink>
        </div>
      </li>
    </ul>
    <a href="javascript:;" class="carousel-btn prev" @click="toggle(-1)">
      <i class="iconfont icon-angle-left"></i>
    </a>
    <a href="javascript:;" class="carousel-btn next" @click="toggle(1)">
      <i class="iconfont icon-angle-right"></i>
    </a>
    <div class="carousel-indicator">
      <span v-for="(item,i) in sliders" :key="i" :class="{active:index===i}" @click="index=i"></span>
    </div>
  </div>
</template>

<script>
import { onUnmounted, ref, watch } from 'vue'
export default {
  name: 'XtxCarousel',
  props:
    {
      sliders: {
        type: Array
      },
      duration: {
        type: Number,
        default: 3000
      },
      autoPlay: {
        type: Boolean,
        default: false
      }
    },
  setup (props) {
    const index = ref(0)

    // 上一张下一张
    const toggle = (step) => {
      const temp = index.value + step
      if (temp > props.sliders.length - 1) {
        index.value = 0
        return
      }
      if (temp < 0) {
        index.value = props.sliders.length - 1
        return
      }
      index.value = temp
    }

    // 自动轮播  防抖
    let timer = null
    const autoPlayFn = () => {
      clearInterval(timer)
      timer = setInterval(() => {
        index.value++
        if (index.value > props.sliders.length - 1) {
          index.value = 0
        }
        // console.log(index.value)
      }, props.duration)
    }
    // 只有数组改变了 就重新调用
    watch(() => props.sliders, (newVal) => {
    //   console.log(newVal)
      // 有数据&开启自动播放，才调用自动播放函数
      if (newVal.length > 1 && props.autoPlay) {
        autoPlayFn()
        // console.log(1)
      }
    }, { immediate: true })

    // 鼠标进入停止，移出开启自动，前提条件：autoPlay为true
    const stop = () => {
      if (timer) clearInterval(timer)
    }

    const start = () => {
      if (props.sliders.length && props.autoPlay) {
        autoPlayFn()
      }
    }
    // 组件消耗，清理定时器
    onUnmounted(() => {
      clearInterval(timer)
    })
    return { index, toggle, stop, start }
  }
}
</script>

<style scoped lang="less">
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
// 轮播商品
.slider {
  display: flex;
  justify-content: space-around;
  padding: 0 40px;
  > a {
    width: 240px;
    text-align: center;
    img {
      padding: 20px;
      width: 230px!important;
      height: 230px!important;
    }
    .name {
      font-size: 16px;
      color: #666;
      padding: 0 40px;
    }
    .price {
      font-size: 16px;
      color: @priceColor;
      margin-top: 15px;
    }
  }
}
</style>
